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The comments that will follow are not scientifically proved, these are just the results of some experiments with broadseaming combined with the experience of kitebuilding for 15 years now. It is rather complex to understand what the effects are of adding volume in some parts of a kitesail. Generally the more billow you have the more lift is created in that part of the sail. Depending on which part of the sail we are talking about the effects will be different. In the nose section more billow means more lift that is more tracking capabilities, more precision, more tension and respons on the lines in normal flight.When in a fade this extra cloth will invert and form a billow that helps to hold the fade, easier backspins, backspincascades etc...For pitchcontrolled moves I can't say if there is an advantage. I think much depends on the depth of that billow, here is some work to do.When the kite does a lazy suzan this nose-billow will act aerodynamically and will pull the nose down, pulling the kite in an even deeper backflipAll these effects are known by a lot of kitebuilders and most of them will use the curve of the leading edge to induce a billow in the nose. Even in some older designs as the Aeri FX and the Matrix the billow was a combination of broadseaming and external cambering.

As a complement of the message above I would say that broadseaming locks the billow on a particular place in the sail. So if you adapt the panellayout to the sections that are involved you can create an accurate billow in a specific area. This billow will be independant of for example wingtiptensioning or frame deformation. Using external cambering via a curve on the leading edge or spine will lead to a billow that is situated in the proximity of this frame-elements. So if you like to have it in the middle of the sailsurface than this broadseaming is an intresting solution.

In flight you can usually feel this extra lift as an extension of windrange in the lower windspeeds, a feeling of aerodynamical efficiency because the kite picks up every little bit of wind and transforms it into power.

Hey Werner nice info in your last post thanks. I get a bit confused though because it seems some kite makers equate billow with sail depth. HOw do you differentiate between the two and which do you prefer to use?

I tried to look this up and indeed the word billow as a noun is not that common. I think 3 dimensional sail depth would be better.

That might work. From what I have read sail depth is supposed to refer to the amount the sail is pushed out by the standoffs and billow is suposed to refer to how much the sail is allowed to be formed by wind pressure to create the desired aero foil shape. I have a kite that has a lot of billow from LS to nose and somewhat centered on the wing as well as a deep sail TE profile and it really seems to be a slug in performance. Weak turtle based tricks(needs to back flip 130deg to get into a turtle and falls out easily without inputs), slow speed and needs easily 4 mph over its stated low wind range just to fly reliably. Have you experienced this in any stages of your designs and is there any way to adjust the billow/sail depth after the kite is made without redoing the sail?

There is not one truth in this context. Without pictures and/ or a video of your kite I can't do any suggestions.Nevertheless, adjusting the sail depth is fairly simple by increasing the aspect-ratio You can do this by shifting the center T to a higher position Then you adjust the LS connectors in order to have the LS horizontal again.

There is not one truth in this context. Without pictures and/ or a video of your kite I can't do any suggestions.Nevertheless, adjusting the sail depth is fairly simple by increasing the aspect-ratio You can do this by shifting the center T to a higher position Then you adjust the LS connectors in order to have the LS horizontal again.

THANKS I have a couple old beginner kites I'm going to tinker on before I start tweaking the higher end kite I have in mind.

I just did some testflying on the 2011. I know now for sure that a leechline is important and also the tension on it. It seems to me that a tension that gives a light buzz in sharp corners is ideal. Straight forward flight is silent. I also shortened the length of the outer standoff with 2 mm and played with tailweight to tune the tazz-ability. At last I tried to make the 2011 more pitchy for easy yoyo and yofades by adjusting the bridle. I need just one testflight to be sure and than it will be released!!

Latest test resulted in the final settings of standoffs and bridle!! Btw it has become a crossed activated bridle kind a gemini UL. I hope to put a short video on this forum later this week. Everything will be prepared to release in the next week.

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